1. Field of the Invention
The present invention relates to a two-axis actuator, and more particularly, to an X-Y stage micro-actuator for use in a data storing system employing a Scanning Probe Microscope (SPM) technique.
2. Description of the Related Art
A data storing system that uses scanning probe microscope (SPM) techniques generally includes a medium as information storage, an actuator for moving the medium in the X-Y directions on a stage, at least one probe having tips for recording information on the medium or for reading information from the medium, and a signal processor for processing information signals.
The multiple probes can read or record multiple information at the same time, and for this purpose, the tip of each probe must approach the medium. Therefore, the probe needs an actuator and a sensor. The actuator deforms the probe in the Z direction so that the tip of the probe can approach to the medium. Then, the sensor reads information on the medium by sensing the deformation of the probe that moves along the medium.
For two-axis actuation, an actuator needs at least three electrodes in case of unidirectional actuation and at least five electrodes in case of bidirectional actuation. According to U.S. Pat. No. 5,536,988, an actuating part having multiple electrodes in one silicon structure can be achieved by insulating a selected region using thermal oxidation. However, this approach requires a very complicated process.
In U.S. Pat. No. 6,445,107, a single stage micro-actuator capable of actuating in two axes while using one electrode, is disclosed to solve the above-mentioned problem.
However, the actuators in the above patents have the drawback of stage inefficiency. The stage for locating the medium is at the same plane as the actuator for generating an electrostatic force, thereby decreasing the information storage capacity due to a narrow stage area.